# st: RE: How to deal with Double hurdles post estimation...

 From "Franken, Jason R." To Subject st: RE: How to deal with Double hurdles post estimation... Date Thu, 2 Jul 2009 10:00:19 -0500

```Ed,

My understanding (from the publications I've seen applying a double hurdle model) is that you report the results for both probit and truncreg (see Katchova and Miranda cited below as an example).  If you want marginal effects computed at the means, they can be obtained by following -probit- or -truncreg- commands with the -mfx- command.

Best,

Jason

Katchova, A.L., M.J. Miranda.  "TWO-STEP ECONOMETRIC ESTIMATION OF FARM CHARACTERISTICS AFFECTING MARKETING CONTRACT DECISIONS."  American Journal of Agricultural Economics,  86,1(February 2004):88-102.

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Edoardo Di Porto
Sent: Thursday, July 02, 2009 4:31 AM
To: statalist@hsphsun2.harvard.edu
Subject: st: How to deal with Double hurdles post estimation...

I've estimated a double hurdle model (Cragg,1971) following the
procedure explained in Mc Dowell et al.
So with a combination of command...
I've estimated a firts stage with "probit" and a second with a "truncreg"
I've the same covariates in both the stage. The dependent variables
are: a dummy in the first stage (of course)
while in the second I've a real positive, Let's call it "Y".
I get my estimates for betas in both the stages...but now I need to compute:
a) the betas for the double hurdle model
b) predict Y for the double hurdle model
c) compute the elasticities  Y/Xi for the double hurdle model.

I guess that: a) it should be the sum of the betas in the first and
second stage ("B1 from probit+B1 from truncreg"...is it true?)
b) could be obtained predicting the probabilities at the first stage
(predict xb) and multiplying those for the predicted values of Y.?..
No idea for c)!...someone knows anything about it.

Ed

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